7-segment LCD for DIY

[aluck]

I want to put a small 4 or 6 digit 7-segment LCD in my next project. HD44780-based boards are way too bulky.

There are several examples of using PCF8566 +  LCD-S301C31, but the last one is hard to get.

Could someone recommend a good compact 7-seg?

[amspire]

What range of sizes do you want?

Do you want a smaller HD44780-type 4 bit parallel interface or a serial interface? Backlighting?

You can start off at the Newhaven site: http://www.newhavendisplay.com/

[aluck]

What range of sizes do you want?

Do you want a smaller HD44780-type 4 bit parallel interface or a serial interface? Backlighting?

You can start off at the Newhaven site: http://www.newhavendisplay.com/

I want a small one, like 10x50 mm, optional backlighting, any interface.

As for Newhaven - they have all varieties of character LCDs, and I need 7-segment one.

[amspire]

Just went to mouser.com, and they have plenty including the 3 digit LCD-301C31 that you mentioned. You can get 4, 5 and 6 digits.

The smallest and cheapest was the LCD-S401M14TF at about $1.74 - 20mm x 10mm outside dimensions. Characters are 4.42mm high.

http://www.lumex.com/specs/LCD-S401M14TF.pdf

I know Digikey and many of the other distributors have similar displays.

Richard

[amyk]

That might be because that model is discontinued. I don't see any other reference to it on the Lumex site.

Note that these are cheap because they're just the glass and crystal. No controller. You need a suitable AC driving signal generator to use them.

[aluck]

Note that these are cheap because they're just the glass and crystal. No controller. You need a suitable AC driving signal generator to use them.

Yes, I understand. My reason for using 7-segs is not the price, but aesthetics.

[TerminalJack505]

I've had good luck with Lumex's static LCDs.  I haven't used the multiplexed displays, however. 

If you have enough I/O pins on your MCU you can skip the PCF8566 and drive a static (non-multiplexed) LCD directly from the MCU.  Some MCUs have LCD drivers as well, which I'm sure you're well aware of.

[aluck]

If you have enough I/O pins on your MCU you can skip the PCF8566 and drive a static (non-multiplexed) LCD directly from the MCU.  Some MCUs have LCD drivers as well, which I'm sure you're well aware of.

I am going to use low-end 8-bit ATMega's, so there's never enough I/O, and no built-in LCD.

Anyway, external LCD driver seems much more reliable - no way I'm going to risk blowing up the whole LCD with DC voltage if my MCU would hang up.

[TerminalJack505]

If you have enough I/O pins on your MCU you can skip the PCF8566 and drive a static (non-multiplexed) LCD directly from the MCU.  Some MCUs have LCD drivers as well, which I'm sure you're well aware of.

I am going to use low-end 8-bit ATMega's, so there's never enough I/O, and no built-in LCD.

Anyway, external LCD driver seems much more reliable - no way I'm going to risk blowing up the whole LCD with DC voltage if my MCU would hang up.

Yep.  I hear ya.

What I've always wanted is something in-between a static LCD and an HD44780-based module.  Basically just a static module with a chip stuck to the back of it.  The chip would be nothing more than a glorified shift register and display driver.  Have one bit for each of the segments (on or off) and some simple interface to shift-in new values.

This would reduce the number of pins to a half-dozen or so and you wouldn't have a clunky software interface or a clunky physical package.

[electrode]

To be honest, the cheapest way to do that would probably just be to grab a PIC or AVR with just enough pins, and program it to multiplex the (eg.) 4 digits continuously with whatever it's told to do via SPI/I2C. Getting that on an SMD package neatly on the back of the 7-segs would be nice, then just a 4 pin header with Vcc, GND, SCL, SDA.

[amyk]

If you have enough I/O pins on your MCU you can skip the PCF8566 and drive a static (non-multiplexed) LCD directly from the MCU.  Some MCUs have LCD drivers as well, which I'm sure you're well aware of.

I am going to use low-end 8-bit ATMega's, so there's never enough I/O, and no built-in LCD.

Anyway, external LCD driver seems much more reliable - no way I'm going to risk blowing up the whole LCD with DC voltage if my MCU would hang up.

Yep.  I hear ya.

What I've always wanted is something in-between a static LCD and an HD44780-based module.  Basically just a static module with a chip stuck to the back of it.  The chip would be nothing more than a glorified shift register and display driver.  Have one bit for each of the segments (on or off) and some simple interface to shift-in new values.

This would reduce the number of pins to a half-dozen or so and you wouldn't have a clunky software interface or a clunky physical package.

The higher-resolution graphic LCDs have this interface, but I don't think any 7-segment ones do.

[sonicj]

maxim has some chips that give you serial/parallel to triplexed alphanumeric/7seg. link

personally, i always liked the "bubble led" displays.  a single dl2416, dl1414, etc would give you your 4 alphanumeric digits with decoder & character generator onboard.

image from the Vintage Technology Association

[azrobbo]

Sparkfun sells 4-digit 7-segment displays with a serial/SPI interface.  They can be found here: http://www.sparkfun.com/products/9765

[Psi]

If you want something cheap, these are quite good value
http://www.jameco.com/webapp/wcs/stores/servlet/Product_10001_10001_2005497_-1

You can even use them on their side with a 5x3/4/5 font.
But you still need a driver/mcu to drive the led matrix.

[aluck]

Sparkfun sells 4-digit 7-segment displays with a serial/SPI interface.  They can be found here: http://www.sparkfun.com/products/9765

Those are:

• LEDs, not LCD
• expensive
• contain a whole Atmega 328 inside (wonder why they wouldn't just put a simple Intel Pentium just to drive 4 digits)

[Bored@Work]

contain a whole Atmega 328 inside (wonder why they wouldn't just put a simple Intel Pentium just to drive 4 digits)

Pentiums are so old school. Apparently each 7 segment display needs a seven + 1 core i7. The eight's core is to drive the decimal point.

[sacherjj]

All Electronics is a surplus parts seller.  Although they usually have enough of a data sheet or link to a proper one that you can figure something out.  They don't seem to have anything on this guy.   Although it is 1" high and you don't define compact.

http://www.allelectronics.com/make-a-store/item/LCD-200/2-DIGIT-LCD/1.html

Digikey also has quite a few 7 seg LCD displays. less that .5" high.

[sonicj]

are you designing a sweet new pager?
-sj

[aluck]

are you designing a sweet new pager?

It's going to be an AD9851 based function generator.

[sonicj]

nice.

i know its not lcd, but these have a classy look imo. driver is built in.

alpha numeric

[T4P]

nice.

i know its not lcd, but these have a classy look imo. driver is built in.

alpha numeric

Wow , "SINGAPORE" Haven't seen anything made here for a long time 

[aluck]

nice indeed.

V - means Vintage

[nessatse]

Sparkfun sells 4-digit 7-segment displays with a serial/SPI interface.  They can be found here: http://www.sparkfun.com/products/9765

Those are:

• LEDs, not LCD
• expensive
• contain a whole Atmega 328 inside (wonder why they wouldn't just put a simple Intel Pentium just to drive 4 digits)

Pentiums don't really exist anymore and it's overkill ... plus expensive .

whoosh!

[aluck]

I am going to borrow a "SARCASM" sign from The Big Bang Theory.

[sacherjj]

I am going to borrow a "SARCASM" sign from The Big Bang Theory.

On another forum I frequent, we have created a convention of using purple text for sarcasm, because there was a collision of smart asses and those with no sense of humor.